This Non-provisional application claims priority under 35 U.S.C. § 119(a) on patent application No(s). 10-2003-0043287 filed in Korea on Jun. 30, 2003, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a cathode ray tube, more particularly, to a cathode ray tube an improved panel structure, in which the thickness of a panel is reduced to an appropriate level, resulting in minimization of cost of manufacture and panel damages during a manufacture process, and improved brightness.
2. Discussion of the Background Art
FIG. 1 illustrates the structure of a related art cathode ray tube.
Referring to FIG. 1, the cathode ray tube includes a panel 1 having a fluorescent screen 4 formed on an inner surface thereof, a funnel 2 connected to the panel 1, an electron gun 8 housed in the funnel 2, emitting electrons, a deflection yoke 9 for deflecting the electron beams in horizontal and vertical directions, a shadow mask 3 with a color selecting function of the electron beams 11, a mask frame 5 for supporting the shadow mask 3, and an inner shield 7 for shielding the influence of a geomagnetic field on the operation of the cathode ray tube.
As to the operation of the related art cathode ray tube with the above structure, the electron beams 11 emitted from the electron gun 8 housed in the funnel 2 are deflected by the deflection yoke 9, and collided with the fluorescent screen formed on the inner surface of the panel 1, displaying a desired image.
FIG. 2 and FIG. 3 illustrate a panel for use in the related art cathode ray tube.
For example, FIG. 2 illustrates a panel 1 whose inner and outer surfaces have designated radii of curvature, and FIG. 3 illustrates a panel 10 whose outer surface is substantially flat while inner surface has a designated radius of curvature.
FIG. 4 is a comparative view of panels illustrated in FIGS. 2 and 3. From the center, the left side shows the panel 10 of FIG. 3 of which outer surface is substantially flat and inner surface has a designated radius of curvature, and the right side shows the panel 1 of FIG. 2 of which inner and outer surfaces have designated radii of curvature.
In recent years, the panel 10 of FIG. 3 having the substantially flat surface has been a mainstream of cathode ray tubes mainly because when the outer surface is flat, image distortions occur much less and there is little reflection from an external light, overall providing a high quality picture image.
Referring to FIG. 4, it is noticed that the panel 10 of FIG. 3 has a greater OMH (a distance from a mold match line to a seal edge line) than that of the panel 1 whose inner and outer surfaces are both curved at designated curvatures.
Because of the above, a total thickness of the panel 10 having the substantially flat outer surface is increased, and thus, a total weight thereof is naturally increased as well.
Besides, a maximum thickness of an end portion 6 between a skirt portion of the panel and an effective surface of the panel is increased, and this in turn causes a difference in thermal conductivity inside a furnace. As a result thereof, the glass of the panel is damaged.
In addition, compared to the panel 1 having curved inner and outer surfaces at designated radii of curvature, the panel 10 with the substantially flat outer surface exhibits a structural weakness especially related to implosion-proof properties. To complement such weakness, manufacturers made the panel 10 thicker. However, this only degraded brightness of the screen.
Therefore, as the thickness of the panel 10 having the substantially flat outer surface is increased, damages are more likely to be made on the glass, and material cost and manufacturing cost are increased.